package main

/**
简单的协程池/任务
 */
import (
	"fmt"
	"time"
)

func worker(id int, jobs <-chan int, results chan<- int) {
	for j := range jobs {
		fmt.Println("worker", id, "started  job", j)
		time.Sleep(time.Second)
		fmt.Println("worker", id, "finished job", j)
		results <- j * 2
	}
}
/**
建立3个协程,并执行顺序执行5个任务
 */
func main() {
	//In order to use our pool of workers we need to send them work and collect their results. We make 2 channels for this.

	jobs := make(chan int, 100)
	results := make(chan int, 100)
	//This starts up 3 workers, initially blocked because there are no jobs yet.

	for w := 1; w <= 3; w++ {
		go worker(w, jobs, results)
	}
	//Here we send 5 jobs and then close that channel to indicate that’s all the work we have.

	for j := 1; j <= 5; j++ {
		jobs <- j
	}
	close(jobs)
	//Finally we collect all the results of the work.

	for a := 1; a <= 5; a++ {
		<-results
	}
}
